Temperature Controlled (Reefer) Shipping: Complete Guide

What is Reefer Shipping?

Reefer shipping refers to the transport of temperature-sensitive cargo in refrigerated containers ("reefers"). Reefer containers are standard ISO containers equipped with a refrigeration unit that maintains a set temperature throughout the voyage. They are used for fresh produce, frozen foods, pharmaceuticals, chemicals, and any cargo that must be kept within a specific temperature range.

How Reefer Containers Work

A reefer container has a refrigeration unit built into one end, powered by the vessel's electrical supply at sea and by a generator or port power on land. The unit circulates conditioned air through the cargo. Temperature is set by the shipper and monitored continuously via data loggers.

Standard reefer temperatures: Frozen (-18°C to -25°C), Chilled (0°C to 4°C), Controlled (any temperature between -30°C and +30°C).

Controlled Atmosphere (CA) Containers

Beyond temperature, some fresh produce requires controlled atmosphere — adjusting oxygen, CO₂, and nitrogen levels in the container to slow ripening. CA containers extend shelf life by 2–4x compared to standard reefer. Used for bananas, avocados, kiwis, and other sensitive fresh produce.

Key Documentation for Reefer Shipments

• Pre-shipment temperature and condition inspection certificate
• Phytosanitary certificate (for fresh produce)
• Health certificate (for animal products)
• Cold treatment certificate (if required — e.g. citrus to USA)
• Standard shipping documents (Commercial Invoice, Packing List, B/L)

Pre-Cooling: Critical Step

The cargo must be at the correct temperature BEFORE loading into the reefer container. A reefer container maintains temperature — it does not cool down warm cargo. Loading warm cargo into a reefer causes the unit to overwork, creates condensation, and typically ruins the shipment. Pre-cool cargo to the required set point in a cold room before stuffing.

Common Reefer Shipping Problems

• Warm cargo loaded: Always pre-cool to required temperature
• Wrong temperature set point: Verify the correct temperature range with buyer specifications
• Power supply interruption: Ensure reefer is connected to shore power at all transit points
• Poor ventilation: Cargo must be stacked to allow airflow — do not block the airflow channels
• No data logger: Always use a calibrated data logger to prove cold chain continuity for insurance and customs

Frequently Asked Questions